Technical Field
The present invention relates to a particle detection system for detecting particles contained in a gas under measurement.
Description of the Related Art
Conventionally, there has been known a particle detection system which includes a sensor main body having an electrification section for electrifying particles such as soot contained in a gas under measurement to thereby produce electrified particles and which detects the particles contained in the gas under measurement through use of the electrified particles. A specific example of such a particle detection system is a particle detection system whose electrification section includes an ion source for producing ions through corona discharge and which electrifies particles (soot or the like) contained in exhaust gas using the produced ions, to thereby detect the amount of particles contained in the exhaust gas. Patent Document 1 discloses a particle detection system which is mounted on a vehicle including a diesel engine and in which a particle sensor 100 serving as a sensor main body and a sensor drive section 110 for controlling the particle sensor 100 are connected through a cable 120. Also, Patent Documents 2 and 3 disclose a particle detection system whose electrification section includes a pair of electrodes overlapping each other to form the shape of a double-wall tube and in which, after PM agglomerates (PM structures (particulate matter structures)); i.e., particles adhering to the surfaces of the electrodes, are previously formed through use of particles contained in a gas under measurement flowing through the space between the electrodes, the gas under measurement is caused to flow, a high voltage is applied between the electrodes to produce electrified PM agglomerates which move between the electrodes, and the particles are detected through use of the electrified PM agglomerates.
Meanwhile, such a particle detection system may lower in particle detection performance or may become unable to detect particles as a result of accumulation of particles on the electrification section. Therefore, some particle detection systems have a heater which burns and removes particles adhering to the electrification section of the sensor main body. For example, in the particle detection system of Patent Document 1, a heater pattern 380 is provided in a sensor unit 300 which is formed of an insulating ceramic and is provided in the particle sensor 100 (the sensor main body). This heater pattern 380 heats the entirety of the sensor unit 300 to 550 to 600° C. to thereby burn soot adhering to a first electrode 322 of a discharge pattern 320, etc.